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"It was a really good first match," Williams said. "I was just trying to get my rhythm on the clay and make the transition."

Williams has never won the French Open, the only Grand Slam event on clay. But she reached the 2002 final and sounded positive about still having a chance.

"I think inherently right now I am a lot more patient," she said. "So when I see that open court I know that it's not necessarily a winner on clay -- so it doesn't look so tempting. I feel smarter, actually.

"I've won almost every [clay-court] tournament I've played and I got to the finals of the French," she added. "I just haven't had that title yet. Some people say 'she's not that good on clay,' but I don't feel that way. At the end of the day it's about how I feel on the court. I'm good on it."